Created new GlyphFunction class
Making ColumnDataSource __init__ automatically handle a dict positional argument, without requiring passing it in explicitly via kwargs as "data={…}"
make _match_data_params handle dict arguments for dataspec values
Moving some helper functions in GlyphFunction further down, and renaming them to have a leading underscore
Renaming GlyphRenderer.dataspecs to dataspecs_with_refs, and making it a class method on HasProps; adding another dataspecs() classmethod
vastly improving implementation of _match_data_params, to handle kwargs and constant colorspecs and "_units" kwargs
Renaming ColorSpec._isconst to isconst and making it a class method
Adding other GlyphFunctions
Fixing up glyphs.py examples to work with new glyph plotting